Rpc::LrAmCompressor

The LrAmCompressor classes used by both the pscf_pc and pscf_pg programs implements a linear-response Anderson mixing (LRAM) algorithm as described in this publication.

Two closely analogous classes named Pscf::Rpc::LrAmCompressor and Pscf::Rpg::LrAmCompressor implement this algorithm for the pscf_pc CPU and program and the pscf_pg GPU-accelerated program, respectively. These two classes implement the same step algorithm and use the same parameter file format, which are documented below.

Step Algorithm

A general discussion of compressor algorithms for PS-FTS is given here.

The LrAmCompressor algorithm ...

Parameter File

The only parameter needed by this algorithm are the error threshhold "epsilon"

LrAmCompressor{
  epsilon      1.0E-4
}

The full parameter file format, including all optional parameters, is shown below:

LrAmCompressor{
  epsilon           float
  maxItr*           int     (default 200)
  maxHist           int     (default 50)
  verbose           int     (default 0)
  correctionRamp*   float   (default 0.9)
  errorType*        string  ("norm", "rms", "max", or "relNorm")
}

Meanings of all parameters are described briefly below:

Label	Description
epsilon	error threshhold
maxItr*	maximum number of iterations to attempt before declaring failure
maxHist*	maximum number of previous states to retain in history
verbose*	verbosity level (lower values are less verbose. Default level = 0)
errorType*	????